Intermittent performance

[John Dixon]

I have a field "theWord", into which letters are added. If a mistake is made
upon entry, the user is able to delete the last character of the field by
clicking on a button that contains the script found below... or by employing
the option key at the same time the user can clear the whole field.

The problem I have is that the first time the user clicks on the field, a
character is deleted. The second time a user clicks on the field then there
is no response, until the user clicks a third time.

I must point out that the cursor does not leave the rect of the button
during these clicks.



on mouseUp
  if the optionKey is "down" then
    put empty into fld "theWord"
    exit mouseUp
  end if
  
  put the number of chars of fld "theWord" into charCount
  put char 1 to (charCount -1) of fld "theWord" into fld "theWord"
end mouseUp

Any ideas why it does not work everytime ?

regards


John Dixon